Lin, Hai-Qing

Abstract [en]

The structural, dynamical, and electronic properties of compressed SrC2 were systematically investigated up to 200 GPa by using ab initio method. Three new phases are obtained by means of evolutionary algorithm. The confirmed most stable structure has C2/c symmetry at zero pressure, which transforms into an orthorhombic Cmcm phase at 4.5 GPa, followed by another orthorhombic Immm phase, which is stabilized at wide pressure range of 21.5-123.5 GPa, and then transformed into MgB2-type phase (space group, P6/mmm). Although SrC2 has similar structural transformation to that of compressed CaC2, SrC2 holds small electron-phonon coupling, which leads to its low superconducting critical temperature (only 1.8 K).